Heat-coil protective device for electric circuits.



L. E. DICKINSON.

HEAT COIL` PROTECTIVE DEVICE FOR ELECTRIC CIRCUITS.

APPLICATION HLED IULY 14.1911.

,273, 1 58. 'Patented July 23, 1918.

connexes?,

Joninueion ci. application Serial No. 92%, filed September "i7, 1915. This application filed July Serial No. lo?.

prorided e heet coil in which the 'neet producing element through which the-current passes is composed of materiel hei/ing high positive temperature coeficientes (iistinguished from the-comparatively lowzeie peinture eoeiiiciens cimrocteriscic or" rcsieconce wires cominoniy used for heating' por poses( This prcpery, combined witfi than of high specific resistance commen in resist ance Wires for heating purposes makes ib possible to employ a. heet producingu element which is economical in space envi has a iow resistance et norma-i temperatures bui. which increases rapidi); in resistance with increase in teinperoture ne no @he imssn'oI Y Y m. rent, such'increase in resieinncc in 'ouin ing more heat to generotefi, Tine coninuee until snicient heeohes .oei I ereted to eiJ-ect ihe reieese of n mein in position by seine cesiiy aisihie f which perinie hooi coii -,o fnncion,

This eppiicaion is o conrinoation oit' my copending (implication Serie-i No. e 228, filed Sept. Si?, 15H5.

in the drawing Figure i ie a seci'ionni View of :i heno coii embed i this ine tion'end 2 is elevation of i ooii shown in v in in@ drawing "L e is. shown n hosiecui nroride with n, sheii of a non-condire- 'A 1 niecerioh such. :is hokcie. hiv/ing one of ii-S ends ciosei by n peliion ini'fkegrni wiih he body noriion thereof :uni the closeri end provide with :z ineiniic cup Q. n,

one of iis ends ihm-ceded lo engage foie 'threads foi-meri centi-:lily in 'd i the close-fi end oi shcii l. fr tube e, l, i s

Specification of Leiters Eaem.

nncfzioni eraciy made of copper and having a. diamei @recher than let of pin 3, is slipped over said pin and heid in n 7given position with respect thereto by ineens of heat softenabie n eterini 5, such as ion' fusing` soicier. Tonnd upon the tube e is e coiiof heur, procincing Wire 6 having one of its ends ottooiieci to tube, he other end thereof being led out diro/lign siii ioi'izne in the Sheii l ond secured to the ciiif. fit the point where he 'Wire is fnsened to the cop here is formed indencoion or recess l,

which serves as n protection for Jthe lending'H ont porion of seid wire. Bein the pin 8- ihe tube projec's beyond the end of ho eoii 6, iihe pin itself amending beyond one who.

it regi be nienfione ifre hein *ehe ideei Winding` i'or use as e. Pennine elemenJ in e b heet coii size-uid possess ion* resistance et no nai ieinperaigures end et the seine time he copaioie of producing suicient hea-'3 under the ecoion of abnorrnei currens to effect the functioning of the heet coil. 4i Winding; composee?` of e. nieteriei hei/ing o high 'positie/e teinpereiure coefficient iuiiiis these requirements andino); be niece. ein eil-oy consisting.; or e iorge percen e oir inoiei.

purpose is an aiioy ce' jing of @proxii'noreiy 70% nickei 30% iron. his inw has positive ieniperoure coehicienb of "proiininincij: O33 por degree ce e spcciie resisonce or' iifa; roiin'is per een e'f-er eche. thereby :fn f

' ihie io use very E"icieno windi'; it occupies bei, iitie space. @eher haring n,

i improvement nseri hereto or o. inzroeriei p proximo-ely 3,5% i': de ci ihe coii. Since he n" c" coii conne' '"e direciy ii resiso expensive toll lines and it represents a de* sided improvement in the manufacture of heat coils. A .Y

As the method of inserting coils of the type in question in a protector strip is well known in the art, being illustrated, for eX- ainple, in Patent 1,057,126 of March 25, 1913, to A. F. BiXon and Patent 944,540 of December 2S, 1909, to NV. L. Coursen, it is thought to be unnecessary to illustrate the method in the present case. In service the heat coil is under spring pressure and in case the solder is softened by abnormal currents in the windings 6, relative movement is permitted between the pin 3 and the tube 1i, allowing said pin to project farther through the tube and in so doing to ground the line in the Well known manner, as illustrated by the patents hereinbefore referred to.A As a result oit the low resistance of the Winding at normal temperatures it will be apparent that comparatively little energy is consumed under normal conditions by the heat coil contemplated by this invention. However, due to the fact that the material of the winding has a high positive temperature coeicientfthis decrease in energy consumption under normal conditions is not obtained `at a sacrifice in operating efliciency et' the heat coil under conditions of abnormal current.

lli/*hat is claimed is:

1. A' protective device for telephone oirr my namethis 12th day of July, A. D. 1917.

comprising a metal sleeve, a pin passing through said sleeve to which it is secured by a heat softenable material, and a heating element composed of an alloy containing more than 50% nickel surrounding a portion of said sleeve.

2. A protective device for telephone circuits comprising a metal sleeve, a pin passing through said sleeve to which it is secured by a heat softenable material, a heating element composed of an alloy consisting of substantially 7 0% nickel and 30% iron surrounding a portion of said sleeve.

3. A protective device for telephone circuits comprising a metal sleeve, a pin passing through said sleeve to Which it is secured by a heat softenable material, and a heating element surrounding a portion of said sleeve and composed of a nickel alloy having a positive temperature coefficient of more than .0018 per degree centigrade adapte/d to be connected in the circuit.

Il. A protective device for telephone circuits comprising a metal sleeve, a pln'passp ing through said sleeve to which it is secured by a heat softenable material, and a heating element surroundingr a portion of said sleeve and composed of a material having a positive temperature noeilcient of more than .0018 per degree oentigrade and a. specific resistance of more than ten microhms per centimeter cube at zero degrees centigrade adapted to be connected in the circuit.

ln Witness whereof I hereunto subscribe LEWS E. DICKINSON. 

